CN113564153A

CN113564153A - Immobilized biocatalyst and preparation method and application thereof

Info

Publication number: CN113564153A
Application number: CN202110827573.1A
Authority: CN
Inventors: 张强; 高信刚; 曹媛; 麻倩; 张薛龙
Original assignee: Beijing Enfi Environmental Protection Co ltd
Current assignee: Beijing Enfi Environmental Protection Co ltd
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2021-10-29

Abstract

The invention provides an immobilized biocatalyst and a preparation method thereof, a microbial catalyst micelle and a sewage treatment method. The preparation method comprises the following steps: step S1, mixing the liquid culture medium and the porous adsorbent to form a mixed culture system; and step S2, inoculating the microbial agent into the mixed culture system for fermentation culture to obtain a cultured system containing the immobilized biocatalyst. Compared with the conventional immobilization technology in the prior art, the service life of the immobilized biocatalyst can reach 3 years and more, the biochemical catalysis efficiency is far superior to that of the common adsorption immobilized catalyst, the stability of the effect can be kept for a long time, the impact of inflow water on a biochemical system is reduced, and meanwhile, the immobilized biocatalyst can be recycled by a simple method, so that the production cost is reduced.

Description

Immobilized biocatalyst and preparation method and application thereof

Technical Field

The invention relates to the technical field of sewage treatment, in particular to an immobilized biocatalyst and a preparation method thereof, a microbial catalyst micelle and a sewage treatment method.

Background

In the process of treating industrial wastewater and black and odorous water, due to the properties of water, the requirements of the process and the like, the treatment efficiency needs to be improved by using a high-efficiency catalyst microbial inoculum in a system frequently, at present, the high-efficiency liquid microbial inoculum is usually used, but the liquid microbial inoculum can run off in the reaction process, the efficiency can be reduced rapidly, and the biochemical catalysis effect can be lost rapidly. Therefore, a stable immobilized high-efficiency biocatalyst is needed to replace liquid microbial inoculum, so that the biological efficiency can be improved, and the efficiency cannot be reduced due to the loss of the microbial inoculum. After the biocatalyst is immobilized, the stability of the biocatalyst on heat, pH and the like is generally improved, the sensitivity of the biocatalyst on an inhibitor is reduced, the biocatalyst can be recycled by a simple method, the improvement of biochemical efficiency can be facilitated, and the production cost is reduced.

Biocatalyst immobilization can be divided into four categories depending on the mode of action between the microorganism and the carrier: carrier binding, cross-linking, system cut-off, carrier separation. Physical adsorption is now widely used.

The physical adsorption method is a method of preparing an immobilized biocatalyst by adsorbing the biocatalyst onto its surface using an adsorption carrier. In production, the bacteria liquid is usually fermented and cultured, and then the bacteria liquid is added into an adsorption carrier for adsorption, and after a period of time, microorganisms are adsorbed on the carrier to form the biocatalyst by means of the actions between organisms and the carrier, including van der Waals force, hydrogen bonds, electrostatic action and the like. However, the immobilized biocatalyst prepared by the adsorption method generally has the defects of fixed microbial biomass, poor repeatability and stability, easy shedding of microorganisms and the like. Therefore, the immobilized biocatalyst obtained by the method easily loses the biochemical catalysis effect due to the loss of microorganisms.

Disclosure of Invention

The invention mainly aims to provide an immobilized biocatalyst and a preparation method thereof, a microbial catalyst micelle and a sewage treatment method, so as to solve the problem of poor sewage treatment efficiency of the biocatalyst caused by microbial agent loss in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing an immobilized biocatalyst, the method comprising: step S1, mixing the liquid culture medium and the porous adsorbent to form a mixed culture system; and step S2, inoculating the microbial agent into the mixed culture system for fermentation culture to obtain a cultured system containing the immobilized biocatalyst.

Further, the ratio of the bulk volume of the porous adsorbent to the volume of the liquid culture medium is 5-20: 100.

further, the specific surface area of the porous adsorbent is 10-10⁴m²Per g, the preferred porous adsorbent has a pore volume of 10 to 10⁵m³The grain diameter of the porous adsorbent is preferably 0.2-0.4 cm.

Further, the porous adsorbent is selected from any one or more of activated carbon, wood chips, porous glass, porous ceramic, a silica-alumina zeolite molecular sieve, porous silica, diatomaceous earth, and polyurethane foam.

Further, the step S1 includes: stirring and mixing the liquid culture medium and the porous adsorbent for the first time to form a first mixed system; sterilizing the first mixed system to obtain a mixed culture system; preferably, the first stirring is carried out at the temperature of 20-30 ℃, and the rotation speed of the first stirring is preferably 120-150 r/min for 1-2 h; the preferred process of sterilization includes: keeping the first mixed system at 110-130 ℃ for 30-60 min, then carrying out second stirring to cool the sterilized first mixed system to 20-30 ℃ and keeping the second stirring for 2-4 h, and further preferably, the rotation speed of the second stirring is 60-80 r/min.

Further, the fermentation culture in step S2 is performed under stirring conditions, preferably at a rotation speed of 120 to 150 r/min.

Further, the microbial agent is a microbial agent for sewage treatment.

Further, the preparation method further comprises the following steps: and step S3, performing solid-liquid separation on the cultured system to obtain the immobilized biocatalyst.

Further, the preparation method further comprises the following steps: carrying out embedding immobilization treatment on the immobilized biocatalyst by adopting an embedding immobilization carrier; the process of the embedding and immobilizing treatment comprises the following steps: preparing an embedding immobilization carrier solution for embedding an immobilization carrier; mixing the embedding and immobilizing carrier solution with the immobilized biocatalyst to carry out embedding and immobilizing treatment on the immobilized biocatalyst; preferably, the process for preparing the entrapping immobilization pellets comprises: mixing an embedding immobilization carrier with a solvent to form a mixed embedding immobilization carrier system; sterilizing an embedding immobilization carrier system to obtain an embedding immobilization carrier solution, wherein the preferred embedding immobilization carrier solution is an aqueous solution with the mass concentration of 1.5-10%, and the preferred process for carrying out immobilization treatment by utilizing the embedding immobilization carrier solution comprises the following steps: stirring and mixing the embedded immobilized carrier solution and the immobilized biocatalyst for the third time at 30-60 ℃ to obtain a second mixed system, wherein the volume ratio of the embedded immobilized carrier solution to the immobilized biocatalyst is preferably 2-3: 1; preferably, the third stirring speed is 60-80 r/min, and the time is 5-30 min; cooling the second mixed system to 20-40 ℃, stopping stirring and standing for 1-3 h; preferably, the entrapping immobilization pellets are selected from any one or more of agar, PVC, silica gel, polyurethane, cellulose acetate, carrageenan, gelatin, alginate, polyacrylamide and polyvinyl alcohol.

According to another aspect of the present invention, there is provided an immobilized biocatalyst obtained by the aforementioned production method, wherein the microorganism of the immobilized biocatalyst is supported on the inner and outer surfaces of the pores of the porous adsorbent.

According to a further aspect of the present invention, there is provided a microbial catalyst micelle comprising a microbial catalyst, the microbial catalyst being an immobilized biocatalyst as described above.

Further, the microbial catalyst micelle also comprises activated sludge, and the weight ratio of the activated sludge to the immobilized biocatalyst is 1: 1-1: 3.

According to still another aspect of the present invention, there is provided a method for treating wastewater, comprising a step of treating wastewater with a biocatalyst, wherein the biocatalyst is the above immobilized biocatalyst, or the biocatalyst is the above microbial catalyst micelle.

By applying the technical scheme, according to the preparation method of the catalyst, due to the strong adsorbability of the porous adsorbent, nutrient components of a liquid culture medium enter rich pores of the porous adsorbent, then microorganisms can enter the pores of the porous adsorbent by utilizing the requirements of microbial growth and fermentation on nutrients, and then directly grow and propagate in large quantities on the pores and the surface of the porous adsorbent, so that the microbial and the porous adsorbent carrier are combined in a co-growth mode and are more compact and less prone to fall off; and because the pore diameter of the porous adsorbent is smaller, the size of the microorganisms after growth and propagation is increased and the microorganisms are stacked together, so that the microorganisms are less prone to fall off and run off from the pores of the porous adsorbent; therefore, in the fermentation culture process, a large amount of nutrient solution is arranged in pores of the porous adsorbent, so that a large amount of microorganisms can be propagated in the pores, and the number of the microorganisms can be larger than that of the microorganisms which are only adsorbed and fixed on the surfaces at present. Compared with the conventional immobilization technology in the prior art, the service life of the immobilized biocatalyst can reach more than 3 years, the biochemical catalysis efficiency is far superior to that of the common adsorption immobilized catalyst, the stability of the effect can be kept for a long time, the impact of inflow water on a biochemical system is reduced, and meanwhile, the immobilized biocatalyst can be recycled by a simple method, so that the production cost is reduced.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As analyzed by the background technology, the high-efficiency liquid microbial inoculum used in the wastewater treatment process and the immobilized biocatalyst obtained by common adsorption in the prior art have the problems of low catalytic efficiency and high cost caused by easy loss of the microbial inoculum, and the invention provides the immobilized biocatalyst and the preparation method thereof in order to solve the technical problem.

In an exemplary embodiment of the present application, there is provided a method for preparing an immobilized biocatalyst, the method comprising: step S1, mixing the liquid culture medium and the porous adsorbent to form a mixed culture system; and step S2, inoculating the microbial agent into the mixed culture system for fermentation culture to obtain a cultured system containing the immobilized biocatalyst.

According to the preparation method of the catalyst, due to the strong adsorbability of the porous adsorbent, nutrient components of a liquid culture medium enter the rich pores of the porous adsorbent, then microorganisms can enter the pores of the porous adsorbent by utilizing the requirements of microbial growth and fermentation on nutrients, and then the microorganisms directly grow and propagate in large quantities on the pores and the surface of the porous adsorbent, so that the microbial and the porous adsorbent carrier are combined in a co-growth mode and are more compact and less prone to falling off; and because the pore diameter of the porous adsorbent is smaller, the size of the microorganisms after growth and propagation is increased and the microorganisms are stacked together, so that the microorganisms are less prone to fall off and run off from the pores of the porous adsorbent; therefore, in the fermentation culture process, a large amount of nutrient solution is arranged in pores of the porous adsorbent, so that a large amount of microorganisms can be propagated in the pores, and the number of the microorganisms can be larger than that of the microorganisms which are only adsorbed and fixed on the surfaces at present. Compared with the conventional immobilization technology in the prior art, the service life of the immobilized biocatalyst can reach 3 years and more, the biochemical catalysis efficiency is far superior to that of the common adsorption immobilized catalyst, the stability of the effect can be kept for a long time, the impact of inflow water on a biochemical system is reduced, and meanwhile, the immobilized biocatalyst can be recycled by a simple method, so that the production cost is reduced.

In order to adsorb as many nutrients as possible in the pores of the porous adsorbent and to satisfy the requirement of as many nutrients as possible for the microbial agent to propagate in the pores, thereby immobilizing as many microorganisms as possible, the ratio of the bulk volume of the porous adsorbent to the volume of the liquid medium is preferably 5 to 20: 100.

in addition, in order to fix as many microorganisms as possible, the porous adsorbent preferably has stronger adsorbability, thereby keeping the adsorptionEnsuring that enough nutrients are contained in pores of the adsorbent for more microbial agents to grow and reproduce, and preferably selecting the porous adsorbent with the specific surface area of 10-10⁴m²Per g, the preferred porous adsorbent has a pore volume of 10 to 10⁵m³The grain diameter of the porous adsorbent is preferably 0.2-0.4 cm. In order to improve the dispersibility of the immobilized biocatalyst in sewage or sludge in the using process, the particle size of the porous adsorbent is preferably 0.2-0.4 cm.

In order to improve the solidifying amount and firmness of the microorganisms, an adsorbent with stronger adsorbability is selected, and preferably, the porous adsorbent is selected from any one or more of activated carbon, wood chips, porous glass, porous ceramic, a silicon-aluminum zeolite molecular sieve, porous silica, diatomite and polyurethane foam.

The porous adsorbents can be purchased or modified on the basis of purchased commodities, and taking activated carbon as an example, the following modification method is provided to further enrich the pore structure:

step one, washing the activated carbon by using deionized water, wherein the activated carbon is washed while stirring, the stirring speed is 60-80 r/min, 30min of washing is carried out each time, the washing liquid is immediately drained after the washing is finished, and the washing is repeatedly carried out for 3-5 times until the supernatant is clear and transparent.

Step two: acid washing, namely soaking the washed active carbon in 0.01-0.02 mol/L HNO₃Soaking in the solution for 2h, and repeating for three times.

Step three: and (3) alkaline washing, namely soaking the acid-washed active carbon in a NaOH solution with the pH value of 12-13 for 2 hours, and repeating the steps for three times.

Step four: and (4) secondary cleaning, namely cleaning the activated carbon after the alkali cleaning by using deionized water until the pH value of the deionized water outlet water is less than 8.5.

In order to ensure that the microbial inoculum can grow and propagate in a good environment to become a dominant strain, and further improve the action efficiency of the target microorganism, step S1 preferably includes: stirring and mixing the liquid culture medium and the porous adsorbent for the first time to form a first mixed system; and sterilizing the first mixed system to obtain a mixed culture system. The liquid culture medium is an enrichment culture medium developed for a high-efficiency microbial inoculum, the culture medium is beneficial to rapid propagation and culture of target microorganisms and can inhibit propagation of mixed bacteria, and a person skilled in the art can select a culture medium composition suitable for the cultured microbial inoculum according to the specific microbial composition in the cultured microbial inoculum, and details are not repeated here.

In order to improve the mixing uniformity of the liquid culture medium and the porous adsorbent, the first stirring is preferably carried out at the temperature of 20-30 ℃, the rotation speed of the first stirring is preferably 120-150 r/min, and the time is preferably 1-2 h. The above control of the conditions for the first mixing allows the liquid medium and the porous adsorbent to be mixed more thoroughly, so that as much nutrient as necessary for the growth of the microorganisms is adsorbed in the pores of the porous adsorbent.

In the above sterilization process, in order to avoid destruction of nutrients of the culture medium as much as possible and achieve sufficient sterilization, it is preferable that the sterilization process includes: keeping the first mixed system at 110-130 ℃ for 30-60 min, then carrying out second stirring to cool the sterilized first mixed system to 20-30 ℃ and keeping the second stirring for 2-4 h, and further preferably, the rotation speed of the second stirring is 60-80 r/min.

The sterilization of the mixed culture system and the control of the sterilization conditions are beneficial to providing a safe and pollution-free environment for the propagation of the microbial agent, and the efficient propagation of the microorganisms and the long-term storage of the microorganisms at the later stage are ensured.

In the step S1 of the above preparation method, in which the porous adsorbent is allowed to adsorb as much nutrient as possible and the microbial agent is inoculated into the mixed culture system for fermentation, the fermentation culture of the above step S2 is preferably performed under stirring conditions in order to ensure that the porous adsorbent carrier adsorbing the nutrient is in a suspended state, thereby allowing the microorganism to be in more complete contact with the nutrient; on the other hand, in the fermentation process, with the consumption of nutrient substances in the pores, new nutrient substances can be supplemented into the pores in time, and more microorganisms are ensured to be fixed on the porous adsorbent, so that the immobilized biocatalyst with high microorganism immobilization amount is prepared, and in order to fully exert the effects, the stirring rotation speed of the step S2 is preferably 120-150 r/min.

The preparation method of the present application is applicable to all microbial agents that require immobilization at present, and in order to prepare an immobilized biocatalyst for wastewater treatment with high efficiency and ensure high efficiency of wastewater treatment, the microbial agent is preferably a microbial agent for wastewater treatment.

The immobilized biocatalyst obtained by the preparation method exists in a liquid post-culture system, and can be directly put into sewage to be treated when being used for sewage treatment. For further storing, transporting or selling the immobilized biocatalyst, it is preferable that the above preparation method further comprises: and step S3, performing solid-liquid separation on the cultured system to obtain the immobilized biocatalyst. After the solid-liquid separation, the solid immobilized biocatalyst can be obtained, and the catalyst is convenient to store, transport and commercialize. The solid-liquid separation method can adopt the solid-liquid separation method commonly used in the prior art, such as filtration, suction filtration, centrifugation, sedimentation and the like, and is not described herein again.

The immobilized biocatalyst obtained by the above preparation method may be used as a conventional biocatalyst, and in one embodiment of the present application, in order to further improve the stability of the above catalyst, it is preferable that the above preparation method further comprises: and (3) carrying out embedding and immobilizing treatment on the immobilized biocatalyst by adopting an embedding and immobilizing carrier. The water-insoluble semitransparent polymer network or film can be formed on the surface of the porous adsorbent through embedding and immobilizing treatment, so that microorganisms positioned on the surface of the porous adsorbent are trapped in the network or film, the loss of the microorganisms fixed on the surface is prevented, meanwhile, the network or film formed through embedding and immobilizing treatment can allow some substances outside to permeate and metabolites of the microorganisms to diffuse out, the microorganisms are not moved, the microorganisms are ensured to play a catalytic role, the loss of the microorganisms is avoided, the stability of the immobilized biocatalyst is further improved, the repeatability and the catalytic efficiency of the catalyst are improved, and the production cost is reduced.

The above-mentioned embedding and fixing process can refer to the embedding and fixing process commonly used in the prior art, and in one embodiment of the present application, it is preferable that the above-mentioned embedding and fixing process includes: preparing an embedding immobilization carrier solution for embedding an immobilization carrier; the entrapping immobilization pellets solution is mixed with the immobilized biocatalyst to perform an immobilization treatment on the immobilized biocatalyst.

In another exemplary embodiment of the present invention, it is preferable that the process of preparing the entrapping immobilization pellets comprises: mixing an embedding immobilization carrier with a solvent to form a mixed embedding immobilization carrier system; and sterilizing the embedding and immobilizing carrier system to obtain an embedding and immobilizing carrier solution, wherein the embedding and immobilizing carrier solution is preferably an aqueous solution with the mass concentration of 1.5-10%. The embedding immobilization carrier is prepared into a solution form, and then the immobilized biocatalyst is embedded, so that the embedding of each position of the immobilized biocatalyst is more uniform.

In order to improve the embedding efficiency, it is preferable that the process of performing the immobilization treatment using the embedding immobilization support solution includes: and stirring and mixing the embedded immobilized carrier solution and the immobilized biocatalyst for the third time at 30-60 ℃ to obtain a second mixed system, wherein the volume ratio of the embedded immobilized carrier solution to the immobilized biocatalyst is preferably 2-3: 1; preferably, the third stirring speed is 60-80 r/min, and the time is 5-30 min; and cooling the second mixed system to 20-40 ℃, stopping stirring and standing for 1-3 h. The second mixed system is preferably screened to obtain immobilized biocatalyst particles with a volume of more than 1 cubic centimeter, so that the immobilized biocatalyst particles are not easily washed away by sewage in practical application, and the service life of the immobilized biocatalyst particles is further prolonged.

The entrapping immobilization pellets may be those commonly used in the art, and preferably, the entrapping immobilization pellets are any one or more selected from agar, PVC, silica gel, polyurethane, cellulose acetate, carrageenan, gelatin, alginate, polyacrylamide and polyvinyl alcohol. Wherein agar, carrageenan, gelatin and alginate are further preferred, so as to further facilitate the embedding stability and the exertion of the microorganism catalysis effect.

In another exemplary embodiment of the present application, there is provided an immobilized biocatalyst in which microorganisms are supported on the inner and outer surfaces of the pores of the porous adsorbent.

Due to the strong adsorbability of the porous adsorbent, nutrient components of a liquid culture medium enter rich pores of the porous adsorbent, and then microorganisms enter the pores of the adsorbent by utilizing the requirement of microbial growth fermentation on nutrients, so that the microorganisms directly grow and propagate in a large amount in the pores and on the surface of the adsorbent, and the microorganisms and the adsorbent carrier grow and combine together more tightly and are less prone to shedding; and because the pore diameter of the adsorbent is smaller, the size of the microorganisms after growth and propagation is increased and the microorganisms are stacked together, so that the microorganisms are less prone to fall off and run off from the pores of the adsorbent; therefore, in the fermentation culture process, a large amount of nutrient solution is arranged in pores of the adsorbent, so that a large amount of microorganisms can be propagated in the pores, and the number of the microorganisms can be larger than that of the microorganisms which are only adsorbed and fixed on the surfaces at present. Compared with the conventional immobilization technology in the prior art, the service life of the immobilized biocatalyst can reach 3 years and more, the biochemical catalysis efficiency is far superior to that of the common adsorption immobilized catalyst, the stability of the effect can be kept for a long time, the impact of inflow water on a biochemical system is reduced, and meanwhile, the immobilized biocatalyst can be recycled by a simple method, so that the production cost is reduced.

In another exemplary embodiment of the present invention, there is provided a microbial catalyst micelle comprising a microbial catalyst, the microbial catalyst being the immobilized biocatalyst described above. Because the immobilized biocatalyst contained in the catalyst micelle has immobilized a large amount of partial microorganisms for treating certain specific pollutants in sewage, the efficient treatment of sewage can be achieved in a short time and can be maintained for a long time.

The microbial catalyst micelle also comprises activated sludge, and the microbial strains in the sludge are richer, so that the microbial catalyst micelle prepared by combining the activated sludge and the activated sludge has better sewage treatment effect. Preferably, the weight ratio of the activated sludge to the immobilized biocatalyst is 1: 1-1: 3. Because the microbial strains contained in the activated sludge are richer, the microbial strains and the quantity contained in the microbial catalyst micelle are more suitable due to the activated sludge and the immobilized biocatalyst with proper proportion, and the efficiency is higher when the activated sludge and the immobilized biocatalyst are used for sewage treatment.

In another exemplary embodiment of the present invention, a method for treating wastewater is provided, which comprises a step of treating wastewater with a biocatalyst, wherein the biocatalyst is the immobilized biocatalyst or the microbial catalyst micelle. Aiming at the high efficiency and the economy of sewage treatment, one immobilized biocatalyst or microbial catalyst micelle can be used independently, and a plurality of immobilized biocatalysts or catalyst micelles can be matched together to treat sewage, so that the high-efficiency sewage treatment effect is achieved.

The advantageous effects of the present application will be further described below with reference to examples and comparative examples.

Preparing a corresponding microbial agent immobilized microbial catalyst for sewage treatment and a microbial catalyst micelle:

the activated carbon used in the following examples is modified activated carbon, and the specific modification method is as follows: firstly, the activated carbon is preliminarily selected according to the following parameters: the specific surface area is 10-1000 m²A pore volume of 100 to 10000 m/g³The particle size is 0.2-0.4 cm; then the modified product is modified according to the following steps: washing with deionized water under stirring at a rotation speed of 80r/min for 30min each time, draining off the cleaning solution immediately after washing, and repeatedly washing for 5 times until the supernatant is clear and transparent; soaking the cleaned active carbon in 0.02mol/L HNO₃Soaking in the solution for 2h, repeating for three times; soaking the cleaned activated carbon in NaOH solution with the pH value of 13 for 2 hours, and repeating the steps for three times; continuously washing the alkali-washed active carbon with deionized water until the pH value of the deionized water outlet water<8.5 to the end; finally obtaining the modified activated carbon.

Preparation of example 1

1) The specific surface area is 100 to 1000m²A pore volume of 100 to 10000 m/g³The active carbon with the particle size of 0.2-0.3 cm and the LD liquid culture medium are stirred and mixed for the first time at the temperature of 20 ℃ according to the volume ratio of 5:100, and a first mixing system is formed after continuous stirring for 2 hours, wherein the stirring speed is 130 r/min; then carrying out secondary stirring sterilization on the first mixed system at 110 ℃, after the secondary stirring sterilization lasts for 30min, cooling to 20 ℃, and continuously stirring for 2h at the rotating speed of 60r/min of the secondary stirring to obtain a mixed culture system;

2) inoculating nitrifying bacteria (Mijin environmental protection technology (Shanghai) Co., Ltd.) for sewage treatment to the mixed culture system, stirring at a stirring speed of 120r/min, performing fermentation culture for 3d according to nitrifying bacteria culture conditions, and obtaining a system after culture of the immobilized nitrifying bacteria.

3) Draining off liquid from the cultured system of the immobilized nitrobacteria by suction filtration, preparing an agar aqueous solution by taking agar as an embedding immobilization carrier and according to the mass ratio of the agar being 2%, sterilizing at 100 ℃ at a stirring speed of 80r/min, and continuously stirring liquid agar after continuing for 30 min; mixing the agar solution and the immobilized nitrobacteria agent according to the volume ratio of 2:1, stirring for the third time at the rotating speed of 60r/min for 10min to obtain a second mixed system, cooling to 25 ℃, stopping stirring, and standing for 1h to finish the embedding and immobilizing treatment of the immobilized nitrobacteria agent, and then washing with clear water for 1-2 times to obtain the final immobilized embedded nitrobacteria agent.

Preparation of example 2

The difference from the preparation example 1 is that the volume ratio of the activated carbon to the LD liquid culture medium is 10:100, and finally the immobilized embedded nitrobacter agent is obtained.

Preparation of example 3

The difference from the preparation example 1 is that the volume ratio of the activated carbon to the LD liquid culture medium is 20:100, and finally the immobilized embedded nitrobacter agent is obtained.

Preparation of example 4

The difference from the preparation example 1 is that the volume ratio of the activated carbon to the LD liquid culture medium is 30:100, and finally the immobilized embedded nitrobacter is obtained.

Preparation of example 5

The difference from the preparation example 1 is that the solid-liquid separation is not carried out on the system after the immobilized nitrobacteria is cultured, and the immobilized embedded nitrobacteria is finally obtained.

Preparation of example 6

The difference from the preparation example 1 is that a COD removing microbial inoculum (Prolo biotechnology (Shanghai) Co., Ltd.) is used as an immobilized strain, and finally the immobilized embedded COD removing microbial inoculum is obtained.

Preparation of example 7

The method is different from the preparation example 1 in that the porous adsorbent is a silicon-aluminum zeolite molecular sieve, and the specific surface area of the porous adsorbent is 10-10³m²(g) pore volume 10 to 10³m³The particle size is 0.2-0.4 cm per gram, and the immobilized embedded nitrobacter is finally obtained.

Preparation of example 8

The difference from the preparation example 1 is that the specific surface area of the porous activated carbon is 10-10⁴m²A pore volume of 10 to 10 g⁵m³The particle size is 0.2-0.4 cm per gram, and the immobilized embedded nitrobacter is finally obtained.

Preparation of example 9

The difference from the preparation example 1 is that the prepared agar solution and the immobilized nitrobacteria agent are mixed according to the volume ratio of 3:1, and finally the immobilized embedded nitrobacteria agent is obtained.

Preparation of example 10

The difference from the preparation example 1 is that the prepared agar solution and the immobilized nitrobacteria agent are mixed according to the volume ratio of 5:2, and finally the immobilized embedded nitrobacteria agent is obtained.

Preparation of example 11

The difference from the preparation example 1 is that the prepared agar solution and the immobilized nitrobacteria agent are mixed according to the volume ratio of 5:1, and finally the immobilized embedded nitrobacteria agent is obtained.

Preparation of example 12

The difference from the preparation example 1 is that the entrapping immobilization pellets are gelatin (E080428, Annaiji chemical technology (Shanghai) Co., Ltd.), and the specific entrapping immobilization steps are as follows: draining off liquid from the system after the immobilized nitrobacter is cultured by suction filtration, preparing a gelatin aqueous solution by taking gelatin as an embedding immobilization carrier and according to the mass ratio of the gelatin of 0.5%, sterilizing at 100 ℃ at a stirring speed of 80r/min, and continuously stirring and cooling to 60 ℃ after the gelatin aqueous solution is kept for 30 min; mixing the prepared gelatin aqueous solution and the immobilized nitrobacteria agent according to the volume ratio of 2:1, stirring for the third time at the rotating speed of 60r/min for 10min to obtain a second mixed system, cooling to 20 ℃, stopping stirring, and standing for 1h to finish the embedding and immobilizing treatment on the immobilized nitrobacteria agent, then washing with clear water for 1-2 times to finally obtain the immobilized embedded nitrobacteria agent.

Preparation of example 13

The difference from the preparation example 1 is that the embedding immobilization carrier is sodium alginate (E080426, Annaiji chemical technology (Shanghai) Co., Ltd.), and the specific embedding immobilization steps are as follows: draining off liquid from a system after the immobilized nitrobacter is cultured by suction filtration, preparing an alginate aqueous solution by taking alginate as an embedding immobilized carrier and according to the mass ratio of 5% of the alginate, sterilizing at 100 ℃ at a stirring speed of 80r/min, and continuously stirring and cooling to 30 ℃ after the solution lasts for 30 min; mixing the prepared alginate aqueous solution and the immobilized nitrobacteria agent according to the volume ratio of 2:1, stirring for the third time at the rotating speed of 80r/min for 10min to obtain a second mixed system, cooling to 20 ℃, stopping stirring, and standing for 3h to finish the embedding and immobilizing treatment of the immobilized nitrobacteria agent, then washing with clear water for 1-2 times to finally obtain the immobilized embedded nitrobacteria agent.

Preparation of example 14

Preparative example 14 differs from preparative example 1 in that,

the immobilized nitrobacteria agent is not subjected to embedding immobilization treatment, and the nitrobacteria agent is finally obtained.

Preparation of example 15

Mixing certain medical intermediate wastewater treatment activated sludge with the immobilized embedded nitrobacter obtained in the preparation example 1 according to the weight ratio of 1:1 to obtain the microbial catalyst micelle.

The application of the prepared immobilized biocatalyst and the microbial catalyst micelle in corresponding sewage treatment comprises the following steps:

application examples 1 to 5 and application examples 7 to 15

The application examples are the application of the immobilized biocatalyst developed aiming at the treatment of certain medical intermediate wastewater.

The ammonia nitrogen of the effluent of the biochemical treatment of certain medical intermediate wastewater exceeds the standard, the ammonia nitrogen is about 20mg/L, and the final effluent ammonia nitrogen is required to be less than 5 mg/L. Because the field is limited, the biochemical efficiency must be improved to reach the standard. The method is characterized in that a liquid nitrifying agent (Mitsu environmental protection technology (Shanghai) Co., Ltd.) is purchased and added into a nitrifying pool, the initial effect is obvious, the ammonia nitrogen in the effluent can reach below 3mg/L, but after 2 days, the ammonia nitrogen in the effluent is more than 5mg/L, after one week, the added liquid agent is completely ineffective, and the ammonia nitrogen in the effluent is recovered to be about 20 mg/L. After analysis, the loss of the nitrifying bacteria agent is found to cause the continuous increase of the content of the ammonia nitrogen in the effluent.

The preparation method comprises the steps of respectively selecting the nitrifying bacteria immobilized biocatalysts prepared in preparation examples 1 to 5 and 7 to 13, the nitrifying bacteria prepared in preparation example 14 and the microbial catalyst micelles prepared in preparation example 15, and respectively adding the immobilized biocatalysts according to the ratio of the volume of the nitrifying bacteria immobilized biocatalysts (or the microbial catalyst micelles) to the volume of a nitrification tank being 1:100, wherein after a biochemical system runs stably, the ammonia nitrogen content of biochemical effluent is greatly reduced, the continuous running time of the system is prolonged, and the ammonia nitrogen content of the effluent is normal.

The amounts of ammonia nitrogen in biochemical effluent and the duration of system operation after application examples 1 to 5 and application examples 7 to 15 were used for the treatment of medical intermediate wastewater are shown in table 1.

TABLE 1

Application examples/comparative examples	Ammonia nitrogen removal rate/%)	System uptime/year
			Application example 1	＞96.0	3.5
Application example 2	＞95.6	3.4
			Application example 3	＞94.0	3.4
Application example 4	＞90.0	4.1
			Application example 5	＞93.0	3.0
Application example 7	＞95.0	3.5
			Application example 8	＞96.4	3.1
Application example 9	＞94.0	3.2
			Application example 10	＞93.2	3.1
Application example 11	＞90.0	3.1
			Application example 12	＞96.1	3.5
Application example 13	＞96.0	4.0
			Application example 14	＞95.0	3.0
Application example 15	＞96.2	4.0

Application example 6

The application example is the application of the immobilized biocatalyst developed for the treatment of the coal-to-liquid wastewater.

The wastewater of the coal-to-liquids process section is subjected to biochemical treatment and then enters a reverse osmosis system to form coal-to-liquids RO concentrated water, the salt content of the coal-to-liquids RO concentrated water is high, the COD is 70-120 mg/L, and the biodegradability is poor.

The independently researched liquid microbial inoculum has an obvious treatment effect on the coal-to-liquid RO concentrated water, the COD of the effluent can reach below 50mg/L, but the salinity of the RO concentrated water is high, so that the self-propagation of the microbial inoculum is not facilitated, the microbial inoculum loss rate is greater than the propagation rate, the biochemical effluent COD is further higher and higher, the liquid microbial inoculum needs to be continuously added in order to maintain the effluent COD below 50mg/L, and the system operation cost is increased.

The immobilized embedded COD removing microbial inoculum prepared in preparation example 6 of the invention is added with immobilized biocatalyst according to the ratio of the volume of the immobilized biocatalyst to the volume of the biochemical pool being 1:100, the system is continuously operated for three years, and the COD of the effluent is always kept below 50 mg/L.

Application example 16

The embodiment is the application of the immobilized biocatalyst developed for certain printing and dyeing wastewater treatment.

The printing and dyeing wastewater has the characteristics of high organic pollutant content, deep chromaticity, large water quality change, low biodegradability and the like, and belongs to industrial wastewater which is difficult to treat. The treatment process of the printing and dyeing wastewater comprises hydrolytic acidification, BAF and coagulating sedimentation, and when the COD of the inlet water of a treatment plant is 500mg/L, the COD of the outlet water is required to be below 50 mg/L. In fact, after the printing and dyeing wastewater treatment system runs stably, the COD of the effluent of the biochemical system is always maintained at about 150mg/L, and after multiple times of debugging, the COD is always ineffective. And (3) purchasing a high-efficiency COD removing microbial inoculum (Mitsu environmental protection technology (Shanghai) Co., Ltd.) and adding the high-efficiency COD removing microbial inoculum into the contact aerobic tank, wherein the initial effect is obvious, the COD of the contact aerobic effluent can reach below 80mg/L, but the effect begins to decline after 3-5 days, the added liquid microbial inoculum is completely ineffective after one month, and the COD of the effluent is recovered to about 150 mg/L. After analysis, the high-efficiency liquid microbial inoculum has poor adhesiveness and serious loss, so that the microbial inoculum completely fails after one month of actual use.

The above immobilized biocatalysts prepared in examples 1 and 6 were prepared according to the present invention. And adding the immobilized biocatalyst into the BAF tank according to the volume ratio of the volume of each immobilized biocatalyst to the volume of the BAF tank being 1:50 to replace part of the filler in the original BAF tank, wherein after the operation is stable, the COD of the effluent of the BAF tank reaches below 60mg/L, and then performing flocculation precipitation to obtain the COD of the effluent below 50 mg/L. Compared with liquid microbial inoculum, the immobilized biocatalyst has higher efficiency and better effect.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

due to the strong adsorbability of the porous adsorbent used in the preparation method of the catalyst, nutrient components of a liquid culture medium enter rich pores of the porous adsorbent, and then microorganisms can enter the pores of the porous adsorbent by utilizing the requirements of microbial growth and fermentation on nutrients, so that the microorganisms directly grow and propagate in large quantities on the pores and the surface of the porous adsorbent, and the microorganisms and a porous adsorbent carrier grow and are combined more tightly together and are less prone to falling off; and because the pore diameter of the porous adsorbent is smaller, the size of the microorganisms after growth and propagation is increased and the microorganisms are stacked together, so that the microorganisms are less prone to fall off and run off from the pores of the porous adsorbent; therefore, in the fermentation culture process, a large amount of nutrient solution is arranged in pores of the porous adsorbent, so that a large amount of microorganisms can be propagated in the pores, and the number of the microorganisms can be larger than that of the microorganisms which are only adsorbed and fixed on the surfaces at present. Compared with the conventional immobilization technology in the prior art, the service life of the immobilized biocatalyst can reach 3 years and more, the biochemical catalysis efficiency is far superior to that of the common adsorption immobilized catalyst, the stability of the effect can be kept for a long time, the impact of inflow water on a biochemical system is reduced, and meanwhile, the immobilized biocatalyst can be recycled by a simple method, so that the production cost is reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of an immobilized biocatalyst, characterized in that the preparation method comprises:

step S1, mixing the liquid culture medium and the porous adsorbent to form a mixed culture system;

and step S2, inoculating the microbial agent into the mixed culture system for fermentation culture to obtain a cultured system containing the immobilized biocatalyst.

2. The preparation method according to claim 1, wherein the ratio of the bulk volume of the porous adsorbent to the volume of the liquid medium is 5-20: 100.

3. the method according to claim 1, wherein the porous adsorbent has a specific surface area of 10 to 10⁴m²Preferably, the porous adsorbent has a pore volume of 10 to 10%⁵m³The particle size of the porous adsorbent is preferably 0.2-0.4 cm.

4. The method according to any one of claims 1 to 3, wherein the porous adsorbent is selected from any one or more of activated carbon, wood chips, porous glass, porous ceramic, a silica-alumina zeolite molecular sieve, porous silica, diatomaceous earth, and polyurethane foam.

5. The method for preparing a composite material according to claim 1, wherein the step S1 includes:

stirring and mixing the liquid culture medium and the porous adsorbent for the first time to form a first mixed system;

sterilizing the first mixed system to obtain the mixed culture system;

preferably, the first stirring is carried out at the temperature of 20-30 ℃, and the rotation speed of the first stirring is preferably 120-150 r/min for 1-2 h;

preferably, the sterilization process comprises: keeping the first mixing system at 110-130 ℃ for 30-60 min, and then carrying out second stirring to cool the sterilized first mixing system to 20-30 ℃ and keep stirring for 2-4 h, wherein the rotation speed of the second stirring is preferably 60-80 r/min.

6. The method according to claim 1, wherein the fermentation culture of step S2 is performed under stirring conditions, preferably at a rotation speed of 120-150 r/min.

7. The method according to claim 1, wherein the microbial agent is a microbial agent for sewage treatment.

8. The method of manufacturing according to claim 1, further comprising:

and step S3, carrying out solid-liquid separation on the cultured system to obtain the immobilized biocatalyst.

9. The method of manufacturing according to claim 8, further comprising: carrying out embedding immobilization treatment on the immobilized biocatalyst by adopting an embedding immobilization carrier;

the embedding and immobilizing process comprises the following steps:

preparing an embedding immobilization carrier solution of the embedding immobilization carrier;

mixing the embedding immobilization carrier solution with the immobilized biocatalyst to carry out embedding immobilization treatment on the immobilized biocatalyst;

preferably, the process of preparing the entrapping immobilization pellets solution comprises:

mixing the embedding immobilization carrier with a solvent to form a mixed embedding immobilization carrier system;

sterilizing the embedding and immobilizing carrier system to obtain the embedding and immobilizing carrier solution,

preferably, the embedding immobilization carrier solution is an aqueous solution with the mass concentration of 1.5-10%,

preferably, the process of performing the immobilization treatment using the entrapping immobilization pellets solution comprises:

stirring and mixing the embedding immobilized carrier solution and the immobilized biocatalyst for the third time at 30-60 ℃ to obtain a second mixed system, wherein the volume ratio of the embedding immobilized carrier solution to the immobilized biocatalyst is preferably 2-3: 1; preferably, the third stirring rotating speed is 60-80 r/min, and the time is 5-30 min;

cooling the second mixed system to 20-40 ℃, stopping stirring and standing for 1-3 h;

preferably, the embedding immobilization carrier is selected from any one or more of agar, PVC, silica gel, polyurethane, cellulose acetate, carrageenan, gelatin, alginate, polyacrylamide and polyvinyl alcohol.

10. An immobilized biocatalyst obtained by the production method according to any one of claims 1 to 9, wherein the microorganism of the immobilized biocatalyst is supported on the inner and outer surfaces of the pores of the porous adsorbent.

11. A microbial catalyst micelle comprising a microbial catalyst, wherein the microbial catalyst is the immobilized biocatalyst of claim 10.

12. The microbial catalyst micelle of claim 11, further comprising activated sludge, wherein the weight ratio of the activated sludge to the immobilized biocatalyst is 1: 1-1: 3.

13. A method for treating wastewater, comprising a step of treating wastewater with a biocatalyst, wherein the biocatalyst is the immobilized biocatalyst of claim 10, or the biocatalyst is the microbial catalyst micelle of claim 11 or 12.